Switch assembly



April 16, 1963 G. A. REESE 3,086,095

SWITCH ASSEMBLY Filed Feb. 8, 1960 3 Sheets-Sheet 1 April 1963 G. A. REESE 3,086,095

SWITCH ASSEMBLY Filed Feb. 8, 1960 3 Sheets-Sheet 2 ,zzz,

6/0, A Reese April 16, 1963 e. A. REEsE 3,086,095

, SWITCH ASSEMBLY Filed Feb. 8, 1960 s Sheets-Sheet a 3,086,095 SWlTCH ASSEMBLY Glenn A. Reese, Canega Park, Calii, assignor to The Magnavox Company, Los Angeles, Calif., a corporation of Delaware Fiied Feb. 8, 196%, Ser. No. 7,242 20 Claims. (Cl. 200-87) This invention relates to a switch assembly in which a plurality of magnetically opera-ted switches are mounted to extend into an annular air gap and to be swept by flux in the air gap so as to provide successive and periodic operations of the switches. The invention is more particularly directed to an improved switching assembly of this type which is quite small and compact and in which the switches operate at precise timed intervals.

Switching assemblies which are capable of operating at extremely high switching rates at precisely timed intervals find wide utility in the electronic and electric arts. A number of such switching assemblies are disclosed in co-pending patent applications filed in the name of the present inventor. These applications include the applications Serial No. 652,968, filed April 15, 1957, and now Patent No. 2,945,931, Serial No. 656,054, filed April 30, 1957, and now Patent No. 2,932,699, Serial No. 753,041, filed August 4, 1958, and now Patent No. 2,988,616, and Serial No. 813,736, filed May 18, 1959. In these copending patent applications, a plurality of magnetically operated switches are mounted to extend into an annular air gap. A magnetic flux is produced throughout the annular air gap and slight flux distortions are introduced at predetermined angular positions around the annular air gap. The components which form the annular air gap and the components including magnets which produce the flux in the air gap are mounted on a rotor which is rotated with respect to the magnetically operated switches. The switches are axially mounted in a1ignment with the longitudinal axis of the rotor at a predetermined distance therefrom. The flux distortions, which are due to the configuration of the rotor, are swept successively past the magnetic switches to provide for this operation. The switches are extremely sensitive and are operated by slight distortions of the flux in the annular air gap.

In each of the above-identified patent applications, the switches are axially aligned, being in alignment with the longitudinal axis of the rotor. In order to provide for the successive operation of the switches, the switches are spaced apart so that such assemblies are bulky when relatively large numbers of switches are utilized. These assemblies are bulky also because the fiux pattern, which is rotated adjacent the switches, is developed by magnets in the rotor. The magnets place a limitation as to how small the rotor can be made.

In a specific illustrative embodiment of this invention, a compact switching assembly of high timing accuracy is provided. For the same number of switches, the assembly occupies a volume which is less than 25 percent of the volume of any of the prior switching assemblies. There are many applications, for example, in airborne equipment, in which such a reduction in size is desirable and occasionally necessary. In the specific illustrative embodiment of this invention, the switches are radially instead of axially disposed with respect to the axis of rotation of the rotor. The radially aligned switches can be closely packed without effecting the timing accuracy of the switching assembly.

The switches extend into in annular groove in the rotor. Features of the invention relate to the utilization of a rotor made of magnetic material with the magnets utilized to develop the magnetic field through the tates Patent ice annular air gap included as part of the stator. The rotor may, accordingly, be made much smaller than when a permanent magnet is required.

In addition to providing for a more compact assembly, the radial disposition of the magnetic switches facilitates their individual removal for inspection or maintenance.

With the switches radially disposed, a small axial movement of the rotor varies the switching interval of each of the plurality of magnetically operated switches by a considerable factor. For example, in the illustrative embodiment, the switches may be operated during successive channels or intervals of 1,750 microseconds. An axial movement of the rotor of one hundredths (0.010) of an inch varies the switching interval in one direction or the other by 400 microseconds. Features of this invention relate to the provision of means for maintaining the timing accuracy in the presence of small axial movements of the rotor. A pair of steel segments are positioned adjacent each of the magnetic switches which efiectively pulse the adjacent switch with a steep wave front pulse responsive to distortions of the flux in the annular air gap. The shape of the wave front is independent of the axial position of the rotor. Small variations in the axial position of the rotor, accordingly, do not vary the timing accuracy of the switching assembly.

Further features of this invention relate to the provision of a magnetic field which assists in maintaining the axial position of the rotor. The rotor has a second annular groove smaller than the annular groove utilized for operating the magnetic switches. Any axial variation in the position of the rotor from a predetermined position develops a magnetic force, due to the second annular groove, in a direction to return it to its normal position.

Further advantages and features of this invention will become apparent upon consideration of the following description when read in conjunction with the drawing, wherein:

FIGURE 1 is a perspective view of a bank of switching assemblies of this invention and of a motor and gear box utilized to drive the switching assemblies;

FIGURE 2 is an exploded perspective view of a number of components utilized in the switching assembly of this invention;

FIGURE 3 is a partially sectionalized perspective view of the switching assembly of this invention with a portion of the stator removed;

FIGURE 4 is a sectional view of the switching assembly of this invention in a plane perpendicular to the longitudinal axis of the rotor and stator of the switching assembly of this invention;

FIGURE 5 is a sectional view of the switching assembly of this invention taken along lines 5--5 in FIGURE 4 illustrating the spacing of the magnetic switches;

FIGURE 6 is a sectional view through one of the magnetic switches utilized in the switching assembly of this invention; and

FIGURES 7a and 7b are schematic representations of the air gap formed in the rotor utilized in the switching assembly of this invention. These two views illustrate the manner in which a movable contact in each of the individual magnetically operated switches utilized in the switching assembly is brought into contact with a fixed contact in the switch as the switch is swept by a variation in the magnetic flux of the angular air gap in the rotor.

Referring first to FIGURE 1, a number of switching assemblies 16 through 27 are positioned side by side and supported by a chassis 13 which may be made of cast metal. Two flanges 13a and 13b on the sides of the chassis i3 engage slots 41 and 42, shown particularly in "It a.)

FIGURES 2 and 3, in each of the switching assemblies 16 througth 27. The switching assemblies 16 through 27 are intercoupled and are operated in synchronism by a motor 14 which is coupled to the switching assemblies 16 through 27 by a gear box 15. Two cables 31 and 32 provide for electrical connections to the switching assemblies' .16 through 27 and a cable 33 provides an electrical connection to the motor 14;. The bank of switching assemblies 16 through 27, the motor 14 and the gear box 15 may together have a weight of 36 pounds and have overall dimensions of by 6 by 19 inches.

The switching assemblies 16 through 27 may readily be removed from the bank or stack of assemblies by unbolting assembly couplings, not shown, and by sliding the assemblies along the flanges 13a and 13b of the chassis 13. As indicated above, each of the assemblies 1-5 through 27 may be of identical construction and the switching assembly 16 shown in FIGURES 2 through 5 is illustrative. As shown in FIGURES 2 through 5, the switching assembly 16 includes a stator 44 which is supported by means of the grooves 4-1 and 42 and the flanges 13a and 1317 on the chassis 13, and a rotor 45 which is positioned concentrically in the stator 40. A shaft 46 extends from one end of the rotor 4-5, and a shaft 36 (FIGURE 4) extends from the other end of the rotor 45. When the switching assemblies 16 through 27 are stacked on the chassis 13, the shaft 46 of each assembly is coupled to the shaft 89 of the adjacent assembly. In eiiect, therefore, the rotors 45 of each of the switching assemblies 16 through 27 are mechanically connected so that they all rotate as a unit. The couplings between adjacent rotors 45 are not shown but each may be in the form of threaded members with one shaft of each rotor being externally threaded and the other shaft being internally threaded so as to mate with the shafts of adjacent rotors.

The stator 44? includes a number of magnetic switches 99 which are radially aligned about the stator 49. In the illustrative embodiment of this invention, there are 30 switches 99 in each of the switching assemblies 116 through 27. With 12 assemblies 16 through 27 and 30 magnetic switches 90 for each assembly, there are 12x30 or 360 switches included in the stacked arrangement depicted in FIGURE 1. As illustrated in FIGURES 3 and 4, the thirty switches 90 of the assembly 16 are positioned between two cylindrical ceramic magnets 50 and 51. The ceramic magnets 50 and 51 are sandwiched between two substantially cylindrically shaped magnetic pole extensions 48 and 49 which may be made of steel or other magnetic substance. Each of the switches 90 includes a relatively thin lower portion 128 which extends through a hole in a non-magnetic ring 70. As depicted in FIGURE 6, and as further hereinafter described, an upper casing 126 of each switch 90 has a lower taper b in the shape of a truncated cone. The non-magnetic ring 70 supports the switches d0 at the taper 15% The switches 90 may be forced into the openings of the non-magnetic ring 70 during assembly.

The non-magnetic ring 7% is supported in grooves 49a and 48a, respectively, in the steel pole extensions 49 and 48. The ceramic magnets 59 and 51 are concentrically positioned with the ring 70 and are mounted along its outer periphery. The ring 70 is non-magnetic, as indicated above, being illustratively made of aluminum and it has a double function of supporting the switch cartridges and in shaping the magnetic fields, hereinafter de scribed, through the rotor and the stator for operating the switches 99.

In addition to the non-magnetic ring 70, the 30 magnetic switches 90 are also supported by a magnetic ring 91. The magnetic ring 91, which is concentric with the nonmagnetic ring 79, may be made of steel. The ring 91 also serves a double function in that it forms a low reluctance path for the magnetic circuit between the ceramic magnets 50 and 51 in addition to supporting the magnetic switches 90.

The various components of the stator 4d, including the magnets 55) and 51, tie magnetic pole extensions 48 and 49, the rings and 91 and a number of pairs of mag netic segments 71 and 72 are all glued together utilizing illustratively an epoxy resin. The arrangement forms a highly compact and rigid structure. The switches 9%, which are held in place by the magnetic ring 91 and the non-magnetic ring 70', may readily be removed from the assembly 16 even when it is in the stacked arrangement illustrated in FIGURE 1. It is therefore unnecessary to decouple the assemblies 16 through 27 in order to remove any of the switches 99 from any of the assemblies 16 through 27.

The lower casings or extensions 123 of each of the magnetic switches extend into an annular air gap formed in the rotor 45. The annular air gap 95 is formed between two magnetic rings 55 and 56 which are supported by a non-magnetic central portion 45a of the rotor 45. The rings 55 and 56 are continuous and may be made of steel, and the non-magnetic central portion 45a may be made of aluminum. As the rotor 45 rotates, the successive portions of the two rings 55 and 56 pass along opposite sides of the magnetic switches 96.

The two ceramic magnets 50 and 51 in the stator 49 generate magnetic fields which are utilized to control the operation of the switches 90 as the rotor 45 rotates. As illustrated in FIGURES 7a and 7b, the switches 9e are positioned closer the steel ring 56 of the rotor Actually, the switches 90 are positioned closer to a protruding lip of the steel ring 56. The steel ring 55 is cut back or grooved at 93 to emphasize the differential positioning of the switches 90. The magnetic fields developed by the two ceramic magnets 50 and 51 are somewhat difierent due to the different shapes of the steel rings '55 and 56 and due to the differential positioning of the switches 90 between them. The steel segments 71 and 72 are small pieces of steel positioned on opposite sides of each of the switches 90. The steel segments '72 are positioned adjacent the upper surface of the steel ring 56 and, therefore, together form a substantially low reluctance path. The steel segments 71, however, are separated by a substantial air gap from the steel ring 55 be cause the steel ring 55 is cut back away from the air gap 95. The field from the magnet 51 is conducted from the magnet 51 through the magnetic pole extension 49 to the steel rotor ring 56, the steel segments 72, into the switch cartridges 90. The magnetic circuit is completed by leakage flux from the magnetic switches 96 through the steel ring 91 back to the ceramic magnet 51. The ceramic magnet 56 provides for a similar magnetic circuit through the steel magnetic pole extension 48, the steel rotor ring 55, the steel segments 71 and the magnetic switches 9t back to the magnet 50.

Due to the air gap between the segments 71 and the steel ring 55, the magnetic circuit through the steel segments 71 has a much greater reluctance than does the magnetic circuit through the steel segments 72. Actually, not all the flux in either magnetic circuit passes through the segments 71 and 72 because some of the flux passes axially through the air gap 95. The segments 71 and 72 are spaced about the stator 4t) to form the low reluctance paths. Between them, however, some of the flux passes directly across the air gap. Because the magnetic circuit through the steel segments 7-1 is of higher reluctance than the magnetic circuit through the segments 72, more of the flux from the ceramic magnet 56 passes through the air gap 95 than does from the ceramic magnet 51. It is solely the shape of the steel rings 55 and '56 which determines the reluctance of the magnetic circuits. The amount of flux introduced by each of the magnetic circuits to the switches is dependent upon their respective reluctance and the fact that the switches 90 are positioned closer to the ring '56.

Due to the fact that the magnets 50 and 51 are supported in the stator 40, the flux pattern developed thereby is stationary. The two rings 55 and '56, which are positioned in the two magnetic circuits developed by the magnets 51 and 59, however, vary the flux paths as they rotate. The steel ring 55 of the rotor 45 includes one or more tongues 57 which extend along the steel segments 71 and into the annular air gap 95 and the steel ring 56 includes one or more grooves 58 which are axially aligned with the tongues 57 to provide an air gap to the steel segments 72. The contour of the annular air gap 95 is varied due to the presence of the tongue 57 and the groove 53 and the low reluctance magnetic circuit described above is interrupted at the groove 58 whereas the higher reluctance circuit through the segments 71 becomes a low reluctance circuit at the tongue 57. As the rotor 45 rotates in the stator 40, these contour variations define changes in the reluctances of the magnetic circuits to produce variations in the magnitude of the flux provided to the magnetic switches 96 from each of the magnets50 and 51. Efiectively, therefore, the tongue 57 and the groove 53 provide for a rotating fiux pattern through the switches 91?. A magnetic armature 124 (FIGURE 6), hereinafter described, included in each of the switches 90 is moved as the tongue 57 and the groove 58 pass adjacent thereto. The tongue 57 and the groove 58, in this manner, provide for an operating flux pulse which is rotated successively adjacent the 30 switches 90 in the switching assembly 16.

The effect of the rotation of the rotor 45 is particularly illustrated in FIGURES 7a and 7b. As shown in FIG- URF. 7a, as the rotor 45 of the switching assembly rotates toward the right, the variation in the flux produced by the tongue 5'7 and the groove 58 approaches the switch 9%. The switch 90 is stationary. As the tongue 57 moves adjacent the switch 90, as illustrated in FIG- URE 7b, a movable contact in the switch 99 is drawn from an upper to a lower fixed contact. This is due to the fact that the tongue 57 effectively reduces the air gap from the rotor steel ring '55, and the groove 58 efiectively increases the air gap from the rotor steel ring 56. When this occurs, the magnet St has a greater efiect on the switch il than the magnet 51 and the switch 9"? is operated. When the continued movement of the rotor i5 moves the tongue 57 and the groove 53 away from the particular switch 96, the rotor ring 56 is then again closer to the steel segments 71 and to the switch 90 than is the ring 55. The armature of the switch 90 is then moved back to its original position adjacent the upper fixed contact of the switch.

Therefore, each time the tongue 57 and the groove 58 are swept adjacent one of the switches 94}, the movable contact on the armature of the switch 90 is first drawn out of engagement with the first fixed contact and into engagement with the second fixed contact. The movable contact is subsequently returned into engagement with the first fixed contact and out of engagement with the second fixed contact. The switch 90 is in this manner pulsed each time a tongue 57 and a groove 58 pass adjacent thereto. This single-pole, double-throw action of each of the switches 90 is positive in both directions with the movable armature being norm-ally held in engagement with the upper fixed contact due to the fiux through the annular air gap 95 and with it being moved by the tongue 5'7 and the groove 53 to the lower contact and then back again to the upper contact when the tongue 57 and the groove 58 pass.

In the particular illustrative embodiment depicted in FIGURE 3, there are two tongues 57 and two grooves 58 in the rotor 45 so that each of the switches 96 is operated twice during each revolution of the rotor 45. The rotor 45 may be rotated at a speed of 20 revolutions per second so that each of the switches 90 is operated forty times each second with each switch being operated during an interval of approximately 1,410 microseconds. An interval of 1,7 50 microseconds is allotted for each channel during which one of the switches 9t? is operated. With an opcrating interval of approximately 1,410 microseconds, the switches 91? are operated during approximately of the 1,750 microsecond interval allotted for each channel and approximately 340 microseconds duration exists between adjacent switch operations. The thirty switches are successively operated during a 52.5 millisecond interval.

Each of the magnetically operated switches 90 may be similar in construction to the switches disclosed in the copending patent applications Serial No. 753,041 and Serial No. 813,736 referred to above. A switch of this type is illustrated in FIGURE 6. The switch, as illustrated in FIGURE 6, includes an upper tubular casing 126 and a lower tubular casing .128, both of which were mentioned above. These casings are shown as being cylindrical but they may also be elliptical with the larger axis of the ellipse extending along the annular gap of the rotor 15 in FIGURE 3. The tubular casings 126 and 128 may be composed of brass illustratively, or the casing 126 may be magnetic serving as a shield for the internal components of the switch. The shield serves to prevent noise pulses from being induced magnetically into the inner active components of the switch and it also reduces any tendency for such pulses to find their way into the electrical circuitry associated with the switch.

As shown in FTGURE 6, the upper tubular casing 126 or" the switching unit has a larger diameter than the lower casing 123 and has a taper 150 at which the switch 90 is supported by the aluminum ring 711. The lower casing 128 is mounted coaxi-ally with the upper casing 126 and is fitted into the upper casing 126, as illustrated. The lower casing 128 is welded or soldered to the bottom of the upper casing 126, as at 129. The lower end of the lower tubular casing 123 of the switching unit is crimped as at 132, and this lower tubular casing is at least partially filled with a damping insulating fluid, such as a light electrical grade oil.

The switch 90 further includes a magnetic armature 124, which is preferably cylindrical in shape and which is adapted to be fitted into the lower tubular casing 128. The armature 124 is composed of any suitable magnetic material, and the outer diameter of the armature is less than the inner diameter of the lower tubular casing. An insulating collar 134 is mounted on the lower end of the magnetic armature 124 for pivotal movement with the armature. This insulating collar 134 has an outer diameter which is slightly greater than that of the annature 124 and less than the inner diameter of the lower tubular casing 128.

The oil in the lower tubular casing 123 forms a cushion for the magnetic armature 124, and a film of oil terms between the insulating collar 134 and the inner surface of the tubular casing 123. This film of oil forms a dynamic pivot for the magnetic armature 124 and the collar 134 relative to the casing at the lower end of the tubular casing 128. This dynamic pivotal action occurs about the collar 134 as a fulcrum.

The switch 9h includes a movable contact which has a cup-shaped configuration. This movable contact 1211 includes a cylindrical end portion 136 of reduced diameter which is inserted in press fit into the free end of the magnetic armature 124. The cup-shaped movable contact 12 is, therefore, supported at the end of the magnetic armature 124 in coaxial relationship with the magnetic armature 124 and in substantial coaxial relationship with the longitudinal axis of the switch 90. In this way, the movable contact 120 is pivota ble with the armature 124.

A tubular insulating member 138 is supported within the upper tubular casing 126. The upper end of the tubular insulating member 138 is open, and the lower end of this member is closed. A group of apertures are formed in the closed lower end of the tubular insulating member 138 to receive a group of fixed contacts 122, 122' and 122", and to receive a pilot tube 143. The pilot tube 143 is supported by the insulating member 138 on the longitudinal axis of the switch 90.

A connection to the movable contact 120 is made by means of a wire 149 which extends downwardly through the center of the pilot tube and into the mouth of the cup-shaped movable contact 120 in a push-fit with the movable contact. A saw-cu t is formed at the end of the cylindrical portion 136 of the movable contact to receive the end of the wire 14? so as to provide a rigid connection between the Wire and the movable con-tact 120. The wire 149 is relatively thin and flexible so that it can adjust its position in accordance with the pivotal movements of the armature 124. The pilot tube 148 may be composed of a gold-silver alloy or other non-magnetic material.

The fixed contact 122 is connected to a connecting wire 146, the movable contact is connected to a connecting Wire 142 which is soldered to the pilot tube 148, and the fixed contact 122 is connected to a connecting wire 146. The fixed contact 122" is not used. As explained in the copending application 753,041, the axial position of the movable contact 120 can be adjusted by moving the wire 149 up or down in the pilot tube 148. This, in turn, serves to adjust the spacing between the movable contact 120 and the flared portions at the lower ends of the fixed contacts 122 and 122'. When the desired spacing has been achieved, the upper end of the pilot tube 148 may be crimped into engagement with the wire 149.

When the magnetically operated switches 90 are inserted into the annular air gap 95 of the rotor 45, the

armature 124 is controlled normally to hold the movable contact 12% in engagement with the flared portion 122a of the fixed contact 122. However, each time a variation in flux is encountered due to a tongue 57 and groove 58, the movable contact 120 moves away from the fixed contact 122 into engagement with the flared portion 122 of the fixed contact 122'. Therefore, the desired singlepole, double-throw action for each magnetically operated switch is achieved.

As shown in FIGURES 4 and 5, the portion of the lower end of the tubular casing 128 below the crimp 132 is removed so that the end appears relatively flattened. Actually, as illustrated in FIGURES 4 and 5, the end of the casing 128 may be flattened after the terminal part below the crimp 132 is removed. The reason for flattening the end of the casing 128 is because the dimensions of the rotor are quite small and the air gap 95 is through a considerable portion of the rotor 45. In order to provide a clearance between the inside diameter of the air gap 95 and the ends of the switches 90, the casings 128 are flattened. The rotor 45 may be quite small because the permanent magnets and 51 are carried, as indicated above, in the stator 40 and not in the rotor 45.

Any displacement of the rotor 40 longitudinally along its axis of rotation tends to vary the timing of the operation of the switches 90. The steel segments 71 and 72 maintain the timing accuracy with small axial movements of the rotor 45. For example, in the absence of the segments 71 and 72, one hundredths of an inch axial movement of the rotor 45 provides for a variation of plus or minus 400 microseconds for a 1,750 microsecond channel. As indicated above, the switches 90 are operated successively during the 1,750 microsecond intervals. A variation of plus or minus 400 microseconds provides for a considerable error in the operating duration of the switches 9d. The steel segments 71 and 72, which are positioned adjacent each of the switches 90, reduce this error considerably because the flux to the switches 90 is actually through the steel segments 71 and 72 instead of directly from the rotor steel rings 55 and 56. As shown particularly in FIGURES 3 and 4, the steel segments 71 and 72 are tapered to direct the flux into the lower tubular casing 128 of the associated switch 90. The steel segments 71 and 72 are positioned over the steel rings 55 and 56 of the rotor 45 independent of its axial position. The flux change at the tongue 57 and the groove 58 is effective at the instant they pass adjacent a pair of segments 71 and 72. The exact instant the flux change passes adjacent the steel segments 71 and 72 does not depend upon the exact axial position of the rotor 45, and the magnitude of the flux change also does not depend upon the exact axial position of the rotor 45.

Though the axial position of the rotor 45 varies the reluctance of the magnetic path from each of the steel rings 55 and 56 directly to the casing 128 of the switch 90, it does not vary the reluctance of the path through the segments 71 and 72 to the casing 128 of the switch 90. In effect, due to the low reluctance of the segments 71 and 72, they distribute the flux from the associated rings 55 and 56 and act as pulses for the switch 90. As the rotor 45 rotates, the flux variation due to the tongue 57 and the groove 58 accordingly energizes the successive pairs of segments 71 and 72 to pulse their associated switches 90. Due to the segments 71 and 72, the timing accuracy is maintained even with small axial movements of the rotor 45.

The rotor 45 is supported by the two shafts 46 and 80, described above, which are in turn respectively supported in bearings and 76 (FIGURE 4). The bearings 75 and 76 are respectively part of cover plates 64 and 74 at the opposite sides of the rotor 45 and the stator 40. The plate 64 is attached to the stator 40 by means of a number of screws 67, and the plate 74 is attached to the opposite side of the stator 40 by means of a number of screws 77. The assembled arrangement is quite compact. Though the tolerance of the plates 64 and 74 and of the bearings 75 and 76 may be quite small, as described above, even small axial movements of the rotor 45 must be compensated for.

The axial position of the rotor 45 is also maintained by providing an annular groove 81 on the steel ring 56 of the rotor 45. The groove 81 is on the ring 56 between the end of the steel segment 72 and the magnetic pole extension 49 (FIGURES 3 and 4). The flux from the ceramic magnet 51 in the stator 40 passes through the magnetic pole extension to the steel ring 56 of the rotor 45 and around the high reluctance groove 81 to the steel segment 72. If the groove 81 is moved out of position either slightly under the segment 72 or under the magnetic pole extension 49, the length of the magnetic circuit is increased. The change in the magnetic circuit or flux path develops a force in a direction to return the rotor 45 to a position centering the groove 81 between the segment '72 and the magnetic pole extension 49. The adjustment provided by the presence of the groove 81 is in this manner a fine compensating means for small variations in the axial position of the rotor 45. Even with this compensation and the small tolerances in the fabrication of the various components, small axial movements of the rotor 45 occur. The pair of steel segments 71 and 72 avoid any reduction in the timing accuracy of the assembly due to such axial variations.

Although this application has been disclosed and illustrated with reference to particular applications, the principles involved are susceptible of numerous other applications which will be apparent to persons skilled in the art. For example, the number of switches may be more or less than 30, and the number of tongues 57 and grooves 58 may be more or less than 2.

The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

I claim:

1. A magnetically controlled switching assembly including, means rotatable on a particular axis and having first and second walls spaced to define a continuous air gap between the walls, said walls being made of a magnetic ma terial and having contours to define a displacement in the air gap in at least one position along the walls, stationary magnetic means magnetically coupled to said rotatable means for producing a magnetic field in the air gap in ac cordance with the contours of the walls defining the air gap, switching means having an elongate shape and also having two operating conditions and disposed in a direction transverse to the particular axis of rotation of the rotatable means, said switching means extending into the air gap of said rotatable means and responsive to variations in the magnetic field to be actuated from one operating condition to the other, and means coupled to said rotatable means for rotating said rotatable means to move said walls adjacent said switchmg means to periodically bring said switching means under the influence of the variations in the magnetic field.

2. A magnetically controlled switching assembly including: a rotor including first and second walls spaced to define a continuous air gap between the walls and provided with contours in at least one wall to define a displacement in said air gap in the direction between the walls, magnetic means coupled to said rotor for producing in the air gap a magnetic flux having uniform characteristics at successive positions in the air gap and eX- hibiting variations in characteristics at the position of displacement and in accordance with such displacement, and at least one switching unit having an elongate casing and having first and second switch contacts electrically and magnetically isolated from the casing and movable relative to each other and having an armature coupled to a particular one of the switch contacts and in spaced relationship to the other contact and responsive to the variations in the magnetic flux to produce a relative movement of the particular contact into engagement with the other contact, means for supporting the switching unit to extend into the air gap in a plane perpendicular to the axis of rotation of said rotor with the armature disposed in the air gap to respond to the variations in the magnetic flux in the air gap, and means for rotating said rotor to produce periodic actuations of the switching unit.

3. A magnetically controlled switching assembly including: rotatable means including first and second walls spaced to define an annular air gap between the walls and having contours to define a displacement in said air gap in at least one position along said walls, a stator having means magnetically coupled to the rotatable means for producing in the annular air gap a magnetic fiux exhibiting variations in the position of displacement in said air gap, said stator also having at least one stationary switching unit extending into the annular air gap, the switching unit including an armature formed at least in part of ma netic material and disposed in the annular air gap and responsive to the variations in the magnetic fiux in the air gap to control the actuation of the switching unit, and means coupled to the rotatable means for rotating the rotatable means to produce relative motion between the magnetic flux in the air gap and the switching unit to bring the armature of the switching unit periodically under the influence of the variations in the magnetic flux.

4. A switching assembly, including: means rotatable on a particular axis and including first and second walls spaced to define a continuous air gap between the walls and having contours to define a displacement in said air gap in at least one position along said walls, means having properties to produce in said air gap a field exhibiting variations at the position of displacement, elongate switching means extending into said air gap and transversely disposed with respect to the particular axis of rotation of said rotatable means, said switching means having two operating conditions and being responsive to the variations in said field to be actuated from one operating condition to the other, and means coupled to said rotating means for producing relative motion between said walls and said switching means to bring said switching means periodically under the influence of the variations in the field.

5. A switching assembly, including: means rotatable on a particular axis and including first and second walls spaced to define a continuous air gap between the walls and having contours to define a displacement in said air gap in at least one position along said walls, means havit ing properties to produce in said air gap a field exhibiting variations at the position of displacement, elongate switching means extending into said air gap and transversely disposed with respect to the particular axis of retation of said rotatable means, said switching means having two operating conditions and being responsive to the variations in said field to be actuated from one operating condition to the other, means coupled to said rotating means for producing relative motion between said walls and said switching means to bring said switching means periodically under the influence of the variations in the field, and segment members magnetically coupled to said elongate switching means and positioned at opposite sides of said switching means to span said air gap to inhibit any timing variation in the operation of the switching means with axial displacements of said rotatable means.

6. A switching assembly, including: means rotatable on a first particular axis and disposed in a particular axial position and including first and second walls spaced to define a continuous air gap between the walls and having contours to define a displacement in said air gap in at least one position along said walls, means having properties to produce in said air gap a field exhibiting variations at the position of displacement, elongate switching means extending into said air gap and transversely disposed with respect to the particular axis of rotation of said rotatable means, said switching means having two operating conditions and being responsive to the variations in said field to be actuated from one operating condition to the other, and means coupled to said rotating means for producing relative motion between said walls and said switching means to bring said switching means periodically under the influence oi the variations in the field, said rotating means including means responsive to an axial movement of said rotating means for developing a force to restore the particular axial position of said rotating means.

7. A switching assembly, including, a rotor rotatable in a particular plane and having a pair of spaced members of magnetic material defining between the spaced members a continuous air gap having contours to define a displacement in the air gap in at least one position of the members, stationary magnetic means concentrically positioned about said rotor for producing in said air gap a field exhibiting variations at the position of displacement, elongate switching means extending into said air gap and transversely disposed with respect to the particular axis of rotation of said rotor, said switching means having two operating conditions and being responsive to the variations in said field to be actuated from one operating condition to the other, and means coupled to said rotor for rotating said spaced members to bring said switching means periodically under the influence of the variations in the field.

8. A switching assembly, including, a rotor rotatable on a particular axis and having two spaced rings of magnetic material defining between the rings a continuous air gap having contours to define a displacement in the air gap in at least one position of the rings, stationary magnetic means concentrically positioned about said rotor for producing in said air gap a field exhibiting variations at the position of displacement, elongate switching means extending into said air gap and transversely disposed with respect to the particular axis of rotation of said rotor, said switching means having two operating conditions and being responsive to the variations in said field to be actuated from one operating condition to the other, means coupled to said rotor for rotating said rings to bring said switching means periodically under the influence of the variations in the field, and segment means of magnetic material magnetically coupled to said elongate switching means and positioned at opposite sides of said switching means to span said air gap for inhibiting axial movements of said rings from afiecting the timing accuracy of the switching assembly.

9. A switching assembly, including, a rotor rotatable on a particular axis and having two spaced rings of magnetic material defining between the rings a continuous air gap having contours to define a displacement in the air gap in at least one position of the rings, stationary magnetic means concentrically positioned about said rotor for producing in said air gap a field exhibiting variations at the position of displacement, elongate switching means extending into said air gap and transversely disposed with respect to the axis of rotation of said rotor, said switching means having two operating conditions and being responsive to the variations in said field to be actuated from one operating condition to the other, means coupled to said rotor for rotating said rings to bring said switching means periodically under the influence of the variations in the field, and a pair of segment members of magnetic material magnetically coupled to said elongate switching means and positioned at opposite sides of said switching means to span said air gap to prevent axial movements of said rings from affecting the timing accuracy of the switching assembly, at least one of said rings of said rotor defining an annular groove for controlling the field through said rings to said air gap to produce a force responsive to an axial movement of said rings in a direction to restore the axial position of the rings.

10. A switching assembly, including, a rotor rotatable on a particular axis and having a pair of annular members of magnetic material defining between the annular members a continuous annular air gap, one of said annular members having at least one peripheral groove, at least one magnetic switch transversely disposed with respect to the particular axis of rotation of said rotor and extending into said annular air gap between said annular members, means having properties to produce a magnetic field through said annular members and exhibiting variations at said peripheral groove, and means coupl d to said rotor for rotating said rotor to obtain a movement of the variations in magnetic field past said magnetic switch, said radially aligned magnetic switch having two operating conditions and being responsive to the variations in the magnetic field to be actuated from one condition to the other.

11. A switching assembly, including, a rotor rotatable on a particular axis and having a pair of spaced members of magnetic material defining between the members a continuous annular air gap, one of said spaced members having at least one peripheral groove, at least one magnetic switch transversely disposed with respect to the axis of rotation of said rotor and extending into said annular air gap between said annular members, means having properties to produce a magnetic field through said annular members and exhibiting variations at said peripheral groove, means coupled to said rotor for rotating said rotor to effectively obtain a rotation of the variations in the magnetic field past said magnetic switch, said magnetic switch having two operating conditions and being responsive to the variations in the magnetic field to be actuated from one condition to the other, and a member of magnetic material positioned adjacent said magnetic switch and extending adjacent the peripheral surface of the annular member with the peripheral groove for providing a low reluctance path from said annular member to said switch and an increased reluctance path at said peripheral groove.

12. A magnetically controlled switching assembly, including, means rotatable 011 a particular axis and having first and second walls spaced to define a continuous air gap between the walls, said walls being made of a magnetic material and having contours to define a displace ment in the air gap in at least one position along the walls, stationary magnetic means ma netically coupled to said rotatable means for producing a magnetic field in the air gap in accordance with the contours of the walls defining the air gap, switching means having an elongate shape and transversely disposed with respect to the axis of rotation of said rotatable means and also having two operating conditions, said switching means extending into the air gap of said rotatable means and responsive to variations in the magnetic field to be actuated from one operating condition to the other, and means coupled to said rotatable means for rotating said rotatable means to move said walls adjacent said switching means to periodically bring said switching means under the influence of the variations in the magnetic field, said stationary magnetic means including a pair of magnets positioned at opposite sides of said switching means.

13. The combination set forth in claim 12 in which the stationary magnetic means further include magnetic pole extensions coupled to each of said magnets for providing low reluctance paths to said rotatable means whereby a magnetic field is developed in the air gap.

14. A switching assembly, including, a rotor rotatable on a particular axis and having a pair of spaced annular members of magnetic material defining between the momcers a continuous annular air gap, one of said annular members having at least one peripheral groove, the other 0 said annular members having an extension of magnetic material extending into said annular air gap opposite to said groove in said one annular member, at least one mag netic switch transversely disposed with respect to the axis of rotation of said rotor and extending into said annular air gap between said annular members, means having properties to produce a magnetic field through said annular members exhibiting variations at said peripheral groove and at said extension, and means coupled to said rotor for rotating said rotor to effectively obtain a rotation of the variations in magnetic field past said magnetic switch, said magnetic switch having two operating conditions and being responsive to the variations in the ma netic field to be actuated from one condition to the other.

15. A switching assembly, including, a rotor rotatable on a particular axis and having two spaced annular members of magnetic material defining between the annular members a continuous annular air gap, one of said annular members having at least one peripheral groove, the other of said annular members having an extension of magnetic material extending into said annular air gap opposite to said groove in said one annular member, at least one magnetic switch transversely disposed with respect to the axis of rotation of said rotor and extending into said annular air gap between said two annular members, means having properties to produce a magnetic field through said annular members exhibiting variations in said peripheral groove and at said extension, and means coupled to said rotor for rotating said rotor to eifectively obtain a rotation of the variations in magnetic field past said magnetic switch, said magnetic switch having two operating conditions and being responsive to the variations in the magnetic field to be actuated from one condition to the other, and magnetic means positioned on opposite sides of said magnetic switch and disposed relative to said annular members for providing low reluctance paths to said switch whereby the strength of the magnetic field at said switch does not depend upon the exact axial position of said rotor.

16. A switching assembly, including, a rotor rotatable on a particular axis and having a pair of spaced annular members of magnetic material defining between the members a continuous annular air gap, one of said annular members having at least one peripheral groove, the other of said annular members having an extension of magnetic material extending into said annular air gap opposite to said groove in said one annular member, at least one magnetic switch transversely disposed with respect to the axis of rotation of said rotor and extending into said annular air gap between said annular members, means having properties to produce a magnetic field through said annular members exhibiting variations at said peripheral groove, and at said extension, said means including a pair of stationary magnets positioned at opposite sides of said switch and encircling said rotor, a non-magnetic stationary ring between said magnets for supporting said switch and for facilitating the shaping of the magnetic fields provided by said magnets, and a magnetic pole extension for each of said magnets and associated respectively with said annular members to provide a low reluctance path from said associated magnet to said associated annular member of said rotor.

17, A magnetically controlled switching assembly, including, rotatable means including first and second walls spaced to define an annular air gap between the walls and having contours to define a displacement in the air gap in at least one position along the walls, means magnetically coupled to the rotatable means for producing in the annular air gap a magnetic flux exhibiting variations in the position of displacement in the air gap, the last mentioned means having at least one stationary switching unit extending into the annular air gap, the switching unit including an armature formed at least in part of magnetic material and disposed in the annular air gap and responsive to the variations in the magnetic flux in the air gap to control the actuation of the switching unit, means coupled to the rotatable means for rotating the rotatable means to produce relative motion between the magnetic flux in the air gap and the switching unit to bring the armature of the switching unit periodically under the influence of the variations in the magnetic fiux, and means disposed relative to the rotatable means for maintaining the rotatable means at a particular axial position to facilitate the production of the magnetic flux in the air gap,

18. A magnetically controlled switching assembly, including, rotatable means including first and second walls spaced to define an annular air gap between the walls and having contour-s to define a displacement in the air gap in at least one position along the walls, means magnetically coupled to the rotatable means for producing in the annular air gap a magnetic flux exhibiting variations in the position of displacement in the air gap, the last mentioned means having at least one stationary switching unit extending into the annular air gap, the switching unit including an armature formed at least in part of magnetic material and disposed in the annular air gap and responsive to the variations in the magnetic flux in the air gap to control the actuation of the switching unit, means coupled to the rotatable means for rotating the rotatable means to produce relative motion between the magnetic flux in the air gap and the switching unit to bring the armature of the switching unit periodically under the infiuence of the variations in the magnetic flux, and means disposed relative to the rotatable means for facilitating the production of the magnetic flux regardless of variations in the axial position of the rotatable means.

19. A switching assembly, including, means rotatable on a first particular axis and disposed in a particular axial position and including first and second walls spaced to define a continuous air gap in an axial direction between the walls and further including means responsive to an axial movement of the rotatable means for developing a force to restore the particular axial position of the rotatable means, means having properties to produce a field exhibiting variations in the air gap, elongate switching means extending into the air gap and having two operating conditions and being responsive to the variations in the field to be actuated from one operating condition to the other, and means coupled to the rotatable means for producing relative motion between the walls and the switching means to bring the switching means periodically under the influence of the variations in the field. 20. A switching assembly, including, means rotatable on a first particular axis and disposed in a particular axial position and including first and second walls spaced to define a continuous air gap in an axial direction between the walls, means disposed relative to the rotatable means for facilitating the production of the magnetic flux across the axial air gap regardless of variations in the axial positioning of the rotatable means, means having properties to produce a field exhibiting variations in the air gap, elongate switching means extending into the air gap and having two operating conditions and being responsive to the variations in the field to be actuated from one operating condition to the other, and means coupled to the rotatable means for producing relative motion between the walls and the switching means to bring the switching means periodically under the influence of the variations in the field.

References Cited in the file of this patent UNITED STATES PATENTS 2,827,531 OBrien Mar. 18, 1958 2,929,896 Ronning Mar. 22, 1960 2,932,699 Reese Apr. 12, 1960 2,932,703 Haberland Apr. 12, 1960 2,988,616 Reese June 13, 1961 

1. A MAGNETICALLY CONTROLLED SWITCHING ASSEMBLY INCLUDING, MEANS ROTATABLE ON A PARTICULAR AXIS AND HAVING FIRST AND SECOND WALLS SPACED TO DEFINE A CONTINUOUS AIR GAP BETWEEN THE WALLS, SAID WALLS BEING MADE OF A MAGNETIC MATERIAL AND HAVING CONTOURS TO DEFINE A DISPLACEMENT IN THE AIR GAP IN AT LEAST ONE POSITION ALONG THE WALLS, STATIONARY MAGNETIC MEANS MAGNETICALLY COUPLED TO SAID ROTATABLE MEANS FOR PRODUCING A MAGNETIC FIELD IN THE AIR GAP IN ACCORDANCE WITH THE CONTOURS OF THE WALLS DEFINING THE AIR GAP, SWITCHING MEANS HAVING AN ELONGATE SHAPE AND ALSO HAVING TWO OPERATING CONDITIONS AND DISPOSED IN A DIRECTION TRANSVERSE TO THE PARTICULAR AXIS OF ROTATION OF THE ROTATABLE MEANS, SAID SWITCHING MEANS EXTENDING INTO THE AIR GAP OF SAID ROTATABLE MEANS AND RESPONSIVE TO VARIATIONS IN THE MAGNETIC FIELD TO BE ACTUATED FROM ONE OPERATING CONDITION TO THE OTHER, AND MEANS COUPLED TO SAID ROTATABLE MEANS FOR ROTATING SAID ROTATABLE MEANS TO MOVE SAID WALLS ADJACENT SAID SWITCHING MEANS TO PERIODICALLY BRING SAID SWITCHING MEANS UNDER THE INFLUENCE OF THE VARIATIONS IN THE MAGNETIC FIELD. 